Removes the restriction on the rotation amount having to be a multiple
of 8, which allows recognizing slightly more complicated bswap+rotation.
gcc/ChangeLog:
* gimple-ssa-store-merging.cc (do_shift_rotate): Relax rotation
constraints to allow for non-multiple of 8 rotations.
(find_bswap_or_nop_1): Relax mask constraints similarly.
(find_bswap_or_nop): Relax rotation amount contraints too.
gcc/testsuite/ChangeLog:
* gcc.dg/optimize-bswapsi-8.c: New test.
Signed-off-by: David Guillen Fandos <[email protected]>
---
gcc/gimple-ssa-store-merging.cc | 23 +++++++----------------
gcc/testsuite/gcc.dg/optimize-bswapsi-8.c | 21 +++++++++++++++++++++
2 files changed, 28 insertions(+), 16 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/optimize-bswapsi-8.c
diff --git a/gcc/gimple-ssa-store-merging.cc b/gcc/gimple-ssa-store-merging.cc
index 9de8e4be1cf..922304cae50 100644
--- a/gcc/gimple-ssa-store-merging.cc
+++ b/gcc/gimple-ssa-store-merging.cc
@@ -271,8 +271,7 @@ do_shift_rotate (enum tree_code code,
if (size > MAX_SYM_BITS
|| count < 0
- || count >= size
- || count % BITS_PER_UNIT != 0)
+ || count >= size)
return false;
switch (code)
@@ -282,10 +281,9 @@ do_shift_rotate (enum tree_code code,
newv[i] = i < count ? 0 : n->n[i - count];
break;
case RSHIFT_EXPR:
- /* Arithmetic shift of signed type: result is dependent on the value. */
+ /* Arithmetic shift of signed type: propagate sign bit.. */
{
- uint8_t fillv = (TYPE_UNSIGNED (n->type) || n->n[size - 1] == 0)
- ? 0 : MARKER_BIT_UNKNOWN;
+ uint8_t fillv = TYPE_UNSIGNED (n->type) ? 0 : n->n[size - 1];
for (i = 0; i < size; i++)
newv[i] = (i + count < size) ? n->n[i + count] : fillv;
}
@@ -678,12 +676,6 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number
*n, int limit)
{
int i, size = TYPE_PRECISION (n->type);
uint64_t val = int_cst_value (rhs2);
- uint64_t tmp = (1 << BITS_PER_UNIT) - 1;
-
- /* Only constants masking full bytes are allowed. */
- for (i = 0; i < size; i += BITS_PER_UNIT, tmp <<= BITS_PER_UNIT)
- if ((val & tmp) != 0 && (val & tmp) != tmp)
- return NULL;
for (i = 0; i < size; i++)
if (((val >> i) & 1) == 0)
@@ -709,13 +701,12 @@ find_bswap_or_nop_1 (gimple *stmt, struct symbolic_number
*n, int limit)
if (type_size > MAX_SYM_BITS)
return NULL;
- /* Sign extension: result is dependent on the value. */
+ /* Sign extension: propagate MSB if necessary. */
old_type_size = TYPE_PRECISION (n->type);
if (type_size > old_type_size)
for (i = old_type_size; i < type_size; i++)
- n->n[i] = (TYPE_UNSIGNED (n->type)
- || n->n[old_type_size - 1] == 0)
- ? 0 : MARKER_BIT_UNKNOWN;
+ n->n[i] = TYPE_UNSIGNED (n->type)
+ ? 0 : n->n[old_type_size - 1];
else
for (i = type_size; i < old_type_size; i++)
n->n[i] = 0;
@@ -1114,7 +1105,7 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number
*n, bool *bswap,
break;
}
- if (!count || count % BITS_PER_UNIT != 0)
+ if (!count)
return NULL;
memcpy (tmp2_n, tmp_n, MAX_SYM_BITS);
diff --git a/gcc/testsuite/gcc.dg/optimize-bswapsi-8.c
b/gcc/testsuite/gcc.dg/optimize-bswapsi-8.c
new file mode 100644
index 00000000000..f24706e1c80
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/optimize-bswapsi-8.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target bswap } */
+/* { dg-require-effective-target stdint_types } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* Test bswap + arbitrary rotation (not just multiple of 8). */
+
+#include <stdint.h>
+
+uint32_t
+swap_and_rotate (uint32_t a)
+{
+ return (a & 0x000000FF) << 23 |
+ (a & 0x0000FF00) << 7 |
+ (a & 0x00FF0000) >> 9 |
+ (a & 0xFE000000) >> 25 |
+ (a & 0x01000000) << 7;
+}
+
+/* { dg-final { scan-tree-dump-times "= __builtin_bswap32 \\\(" 1 "optimized"
} } */
+/* { dg-final { scan-tree-dump-times " r>> 1;" 1 "optimized" } } */
--
2.55.0
